Since updating to -current at svn r338350, we're seeing this panic twice a day. I'm having trouble getting the panicstr, but this should point at the location of the issue. db> bt Tracing pid 0 tid 100278 td 0xfffff8001430b000 ip6_savecontrol_v4() at ip6_savecontrol_v4+0x26/frame 0xfffffe00955f75f0 ip6_savecontrol() at ip6_savecontrol+0x2c/frame 0xfffffe00955f7640 icmp6_input() at icmp6_input+0x24a2/frame 0xfffffe00955f7800 ip6_input() at ip6_input+0xc43/frame 0xfffffe00955f78f0 netisr_dispatch_src() at netisr_dispatch_src+0xa8/frame 0xfffffe00955f7940 ether_demux() at ether_demux+0x140/frame 0xfffffe00955f7970 ether_nh_input() at ether_nh_input+0x317/frame 0xfffffe00955f79c0 netisr_dispatch_src() at netisr_dispatch_src+0xa8/frame 0xfffffe00955f7a10 ether_input() at ether_input+0x26/frame 0xfffffe00955f7a30 _task_fn_rx() at _task_fn_rx+0x8e6/frame 0xfffffe00955f7b20 gtaskqueue_run_locked() at gtaskqueue_run_locked+0x144/frame 0xfffffe00955f7b80 gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0x98/frame 0xfffffe00955f7bb0 fork_exit() at fork_exit+0x83/frame 0xfffffe00955f7bf0 fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe00955f7bf0 --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
I can't seem to get this to happen at r338426 I'll keep an eye out for it as we progress, but I think we'll close it for the time being.